Add Solcore to conda package manager

[dalonsoa]

Solcore can be installed using pip but it will be convenient to have it available also with conda, especially because the later is broadly used by the scientific community - and also to give more options.

Whether it is default conda channel or conda-forge (another popular channel) does not matter much as long as:

• it takes into account that Solcore incorporates some fortran code; as in the case of pip it will be desirable that the user does not need any fortran compiler to install Solcore from conda
• the pipeline to create and upload the package can be integrated in GitHub Actions, so a new version can be updated automatically whenever there's a new release